Impact of Coastal Morphology, Structure and Seismicity on the Tsunami Surge

Murthy, K. S. R.; Subrahmanyam, V.; Murty, G.P.S.; Rao, K.M.

doi:10.1201/9780203964439.ch2

Cited by 3 publications

(9 citation statements)

References 4 publications

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“…The subsurface mapping in this basin further revealed that two prominent cross trends such as the Vedaranyam-Tiruchirapalli and Madurai-Rameswaram cut across the general NE-SW trending rift related horst-graben structural features (Prabhakar and Zutshi 1993). Some of the Precambrian structural elements such as the Palghat-Cauvery and Moyar-Bhavani shear zones extend into the offshore (Subrahmanyam et al 2006). Morphotectonic studies in the offshore areas further revealed the signatures of recent deformation (Ramasamy and Balaji 1995) and differential tectonic movements off Pondicherry (Ramasamy et al 2001).…”

Section: Regional Tectonic Set-upmentioning

confidence: 99%

“…Further, the deep offshore morphology is characterized by very steep continental slope that is distinctly different from rest of the ECMI. This characteristic morphological expression of the shelf-slope areas of this margin caused the higher run-up heights and inundation along the Nagapattinam-Cuddalore coast during the 26 December 2004 major tsunami event (Murthy et al 2006(Murthy et al , 2012. Further, the Cauvery offshore is also characterized by the occurrence of marine geohazards such as the slope instability and slope canyons (Bastia et al 2011).…”

Section: Topography Mapmentioning

confidence: 99%

“…The trends of major shear zones such as Moyar-Bhavani and Palghat-Cauvery are clearly revealed on the aeromagnetic anomaly map in the onshore (Reddi et al 1998). Subrahmanyam et al (2006) identified three major faults (marked F1, F2, and F3 in figure 3) cutting across the E-W trending shear zones in the onshore and extension of these structural trends into the Cauvery offshore. Additionally, in the offshore, a broad magnetic low (∼-200 nT) bounded by highs on either side (in north and south) is noticed between Mahabalipuram and Chennai.…”

Section: Composite Magnetic Anomaly Mapmentioning

confidence: 99%

“…The basin encompasses vast offshore segment and continues into the deep water areas of the eastern offshore of India (Bastia et al 2010). On the basis of offshore magnetic anomalies, Subrahmanyam et al (2006) inferred the continuation of onshore Precambrian structural grain/major lineaments in the Cauvery offshore. In the adjoining Krishna-Godavari basin, integration of Deep Seismic Sounding (DSS) studies in the onshore (Kaila et al 1990) and the multi-channel seismic (MCS) reflection profiles in the offshore (Radhakrishna et al 2012a) along with the gravity interpretation provided valuable information of the crustal structure and early breakup history in the central segment of the Eastern Continental Margin of India (ECMI).…”

Section: Introductionmentioning

confidence: 98%

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Crustal structure and rift tectonics across the Cauvery–Palar basin, Eastern Continental Margin of India based on seismic and potential field modelling

et al. 2016

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The Cauvery-Palar basin is a major peri-cratonic rift basin located along the Eastern Continental Margin of India (ECMI) that had formed during the rift-drift events associated with the breakup of eastern Gondwanaland (mainly India-Sri Lanka-East Antarctica). In the present study, we carry out an integrated analysis of the potential field data across the basin to understand the crustal structure and the associated rift tectonics. The composite-magnetic anomaly map of the basin clearly shows the onshore-tooffshore structural continuity, and presence of several high-low trends related to either intrusive rocks or the faults. The Curie depth estimated from the spectral analysis of offshore magnetic anomaly data gave rise to 23 km in the offshore Cauvery-Palar basin. The 2D gravity and magnetic crustal models indicate several crustal blocks separated by major structures or faults, and the rift-related volcanic intrusive rocks that characterize the basin. The crustal models further reveal that the crust below southeast Indian shield margin is ∼36 km thick and thins down to as much as 13-16 km in the Ocean Continent Transition (OCT) region and increases to around 19-21 km towards deep oceanic areas of the basin. The faulted Moho geometry with maximum stretching in the Cauvery basin indicates shearing or low angle rifting at the time of breakup between India-Sri Lanka and the East Antarctica. However, the additional stretching observed in the Cauvery basin region could be ascribed to the subsequent rifting of Sri Lanka from India. The abnormal thinning of crust at the OCT is interpreted as the probable zone of emplaced Proto-Oceanic Crust (POC) rocks during the breakup. The derived crustal structure along with other geophysical data further reiterates sheared nature of the southern part of the ECMI.

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Section: Regional Tectonic Set-upmentioning

confidence: 99%

Section: Topography Mapmentioning

confidence: 99%

Section: Composite Magnetic Anomaly Mapmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Crustal structure and rift tectonics across the Cauvery–Palar basin, Eastern Continental Margin of India based on seismic and potential field modelling

et al. 2016

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“…Therefore, extensive studies were carried out in the areas of individual hazards such as storms, cyclones, by several researchers in the North Indian Ocean, Arabian Sea and the Bay of Bengal shores. [4][5] [6]. Similar studies have been carried out in countries like Taiwan where the typhoon approach causes strong winds and low atmospheric pressure to create a storm surge.…”

Section: Introductionmentioning

confidence: 96%

Cyclone vulnerability assessment of cuddalore coast in Tamil Nadu, India using remote sensing, and GIS

et al. 2018

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Over the years, cyclones have left a deep and dark footprint on the coastal region of the Cuddalore district in southeast India, which was one of the worst affected districts in the mainland. These disasters over the past several years have revealed the differential impacts due to social structure, economic conditions, and level of infrastructure. Therefore, there is a need for strategies to address the aspects of socioeconomic and infrastructural vulnerability. Cuddalore district is one of the most vulnerable districts for Cyclone. The present study investigates the vulnerability of eastern coastal states of India from potential cyclones using Remote Sensing and GIS. Mapping of cyclone vulnerability zone on 1:50000 scale along the Tamil Nadu coast has been carried out using Remote Sensing and GIS techniques with six physical parameters such as elevation, wind speed, historical cyclone event significant wave height, probable maximum precipitation, and Landuse and Landcover. The regular rank and weight method have been used to integrate the above parameters to achieve the cyclone vulnerability zone map. The resultant cyclone vulnerability zone map has been divided into five cyclone vulnerability categories, namely very high, high, moderate, low, and very low. The output of the study showed significant results, which reflect that the entire northern coastal taluks come under very high cyclone vulnerability zone whereas central and southern coastal taluks fall under high to low cyclone vulnerability zone. This information would serve useful in advanced planning to minimize associated cyclone losses and reduce threats to future coastal development.

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Baseline geophysical data for hazard management in coastal areas in relation to earthquakes and tsunamis

Murthy

2016

The International Journal of Ocean and Climate Systems

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A systematic study of geophysical data of the Eastern Continental Margin of India was taken up to identify the land-ocean tectonic lineaments over the east coast of India and the possible neotectonic activity associated with them. These studies helped in delineating the offshore extension of some of the coastal lineaments. Analysis of magnetic, gravity and shallow seismic data, combined with reported seismicity data, indicates moderate seismicity associated with some of these land-ocean tectonics of the Eastern Continental Margin of India. The coastal/offshore regions of Vizianagaram (north of Visakhapatnam) and Ongole of the Andhra Pradesh margin and the Puducherry shelf of the Tamil Nadu margin have been identified as zones of weakness where neotectonic activity has been established. Bathymetry data over the Eastern Continental Margin of India revealed the morphology of the shelf and slope of this margin, which in turn can be used as the baseline data for tsunami surge models. Detailed bathymetry map and sections of the Nagapattinam-Cuddalore shelf (from 10.5° to about 12°N) indicate that one of the main reasons for the higher run-up heights and inundation in the Nagapattinam-Cuddalore coast during the Indian Ocean Tsunami of 26 December 2004 could be the concave shape of the shelf with a gentle slope, which might have accelerated the tsunami surge to flush through at a rapid force. Structural control also appears to be a contributing factor for the tsunami surge.

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Impact of Coastal Morphology, Structure and Seismicity on the Tsunami Surge

Cited by 3 publications

References 4 publications

Crustal structure and rift tectonics across the Cauvery–Palar basin, Eastern Continental Margin of India based on seismic and potential field modelling

Crustal structure and rift tectonics across the Cauvery–Palar basin, Eastern Continental Margin of India based on seismic and potential field modelling

Cyclone vulnerability assessment of cuddalore coast in Tamil Nadu, India using remote sensing, and GIS

Baseline geophysical data for hazard management in coastal areas in relation to earthquakes and tsunamis

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